


I'll be there (when your reality drowns)

by Doodsxd



Category: Stranger Things (TV 2016)
Genre: Alternate Universe - Creatures & Monsters, Alternative Universe - Sirens & Mermaids, Animal Instincts, Bisexual Steve Harrington, Car Sex, Crush at First Sight, Explicit Sexual Content, Fate & Destiny, Humor, M/M, Making Out, Mates, Mermaid Billy, Merman Billy, Neil Hargrove's A+ Parenting, Possessive Behavior, Post-Season/Series 03, Returning Home, Robin Buckley & Steve Harrington Friendship, Romance, Siren Billy, Steve Harrington Needs a Hug, True Mates
Language: English
Status: Completed
Published: 2020-06-02
Updated: 2020-06-02
Packaged: 2021-03-03 19:08:31
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 7,882
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/24510583
Author URL: https://archiveofourown.org/users/Doodsxd/pseuds/Doodsxd
Summary: Steve couldn’t believe he was doing this.Then again, with his curiosity history, it wasn’t all that unbelievable.The thing was, after Starcourt, they were pretty sure Billy Hargrove was dead. Like, dead dead, gone, you know? Which was a reasonable assumption, considering, you know, his chest was kinda carved like a pumpkin by the Mind Flayer.So imagine their surprise when, after having his body taken by Owens and his goons, Billy Hargrove simply reappeared smoking on the school grounds like nothing ever happened.And yes, they all received the weird apology notes.But, well. Steve’s note had an extra line that saidmeet me at the lake next Wednesday, 7pm.And Steve, the idiot, was going.
Relationships: Billy Hargrove/Steve Harrington
Comments: 16
Kudos: 205





	1. Part I

**Author's Note:**

> Well, hello  
> Liquidsky kinda asked and I made a list and I'm not sure this is it, but... oh well. IDK.  
> Hope you enjoy anyway.

PART I 

Steve couldn’t  _ believe _ he was doing this. 

Then again, with his curiosity history, it wasn’t all that unbelievable. 

The thing was, after Starcourt, they were pretty sure Billy Hargrove was dead. Like,  _ dead _ dead, gone, you know? Which was a reasonable assumption, considering, you know, his  _ chest _ was kinda carved like a pumpkin by the Mind Flayer. 

So imagine their surprise when, after having his body taken by Owens and his goons, Billy Hargrove simply reappeared smoking on the school grounds like nothing ever happened. 

“He doesn’t tell me anything.” Max told them, chewing on a pb&j sandwich. “But he’s been nicer. Got into a huge fight with Neil on the first day back because he was yelling at me for taking the remote control.” The girl shrugged. “Apologized and everything.” 

And yes, they all received the weird apology notes. Some of the group accepted it (Will, Lucas, El), some were dubious about it (Steve, Dustin), and Mike only accepted because Will and El accepted it and he was too much of a coward to disagree with them. 

But, well. Steve’s note had an extra line that said  _ meet me at the lake next Wednesday, 7pm.  _

And Steve, the idiot, was  _ going.  _ Even though the lake was like a seven minute walk from the closest parking space, a dark and uneven descent to murky waters. Steve knew the path, but on that particular night, he was just thankful he had the full moon’s light to guide him. 

The light reflected on the placid lake water, but other than a few dragonflies, there was nothing there. 

“Hello?” Steve said, feet cracking twigs the only sound around other than a hooting owl. “Hello?” 

A few minutes passed. Nothing. 

“He screwed me over.” He concluded, anger boiling inside of him. He hadn’t changed at all, the fucker. Got Steve out there, in the dark, in the middle of the woods, just for kicks and giggles. He would probably mock him the following day during his shift on Family Video-

His thoughts were interrupted, though, by  _ something _ . Something moving in the water, right at the deepest part of the lake. 

Steve took a step forward to see better, frowning. The Upside Down was closed, right? Eleven would have told him- they would have warned him if…

But no tentacles, no slimy skin, no dark alien flowers ready to eat him - just wet blond hair, electric blue eyes and full lips, all wet by lake water. He looked ethereal underneath the moonlight. 

“Holy fuck, what the hell, Hargrove?” Steve yelled, heart on his throat. “Why-? How-? Aren’t you  _ freezing _ -?”

“Hey, Harrington.” Hargrove advanced without using his hands, was he… was he walking underneath that water? But it was so fucking  _ deep _ !

“What the hell are you doing in that water?” He asked as he got closer and closer. 

“We need to have a talk.” He said, arriving at the shallower part of the water. You see, that lake was a bit like a pool, its levels coming and going with rains and winds, shaping its depths and rises. So when he pulled himself to sit at on of those rising shapes of the sand underneath him -  _ that _ was when Steve could  _ see _ or  _ notice _ anything. 

“What the  _ fuck- _ ?” 

“Told ya, pretty boy.” Billy had half a smile on his face, red  _ fish tail _ swishing side to side as he got comfortable. “We gotta talk.”

______________________________________________________

“Did the Upside Down…?” Steve asked him, a little calmer, a few minutes afterwards. 

“That other monstrous world? No.” Billy shook his head. “I was always like this. When in contact with water in a natural space, like this, my legs turn into…” 

“A tail.” Steve continued, still in shock despite the calm exterior. “Like a mermaid’s tail.” Holy fuck, Billy was  _ hot _ . 

“My ma changed too.” Billy explained. 

“But I’ve seen you enter a pool before, you-?” He wondered if he would have noticed, though, with that  _ ass _ inside that skimpy red swim  _ thing- _

Billy sighed. “It comes a time when the change gets limited to one time of the month: the full moon. I can’t change anytime other than that.” 

“Why?” 

“Puberty, I suppose.” Billy shrugged. “One can’t just be a fertile half-siren out there without a mate.” 

Steve narrowed his eyes. “Like… like penguins, or something?” 

“Kinda.” Billy agreed. “It’s one of those things that ensures genetic variability, so we’ll blend in and procreate amongst humans. Or so my ma told me.” He said. “When you are half-siren, during childhood, you can change anytime. But then puberty hits, and you only get one change a month until we find a mate who can help with everything that changing entails.” 

“And what does it entail?” Steve asked, curious now, shifting closer on the stone he was sitting. “I mean. Besides the tail, and breathing underwater.” 

“A few things.” Billy explained. “It’s better if I just show you.” 

“Show me-?” 

Before he could react, Billy had pulled him underwater. 

__________________________________________________________

At first, Steve thought he was going to drown, what with Billy’s arm around his waist pulling him deeper and deeper into the water. He hadn’t taken enough of a breath to be able to swim up at this point. 

Steve struggled against the arms around him, holding his breath. Billy’s scales were really slippery though, impossible to struggle against, and his skin inhumanly smooth for him to get any good grip. 

Finally, though, something else - he wasn’t sure  _ what _ -?

_ Just breathe, pretty boy _ .

The voice in his head surprised him, making him snap from his struggles. 

He turned, looking at Billy, who never took his hands from Steve - although now he had black claws, black eyes, small fangs, and his hair flying a crown around him -- too intently to be a mere coincidence. He felt gold,  _ gold _ ,  _ irresistible- _

_ Trust me. _ The voice repeated.  _ Billy’s _ voice.  _ I don’t want you dead, pretty boy, I swear. Just breathe. _

At this point, it wasn’t really about  _ trust _ . Steve was losing all his oxygen to the nervous beating of his heart. There was nothing he could do to avoid his lungs caving in and  _ breathing _ , inhaling the murky water around him. 

He thought he would drown. He thought he would be  _ dead _ , with no notice to anyone of where he was or what happened to him. He hadn’t told anybody where he was going that night, and fuck if he knew where his parents were on the globe at that point. They’d probably find his body rotten when summer came - maybe even Dustin, for fuck’s sake. 

He thought it would hurt, too, but… inhaling the water actually felt good. Like… like…

_ What the fuck? _

_ Told ya, pretty boy.  _ Billy smirked, amused.  _ I have no intention of having you dead. _

Steve inhaled again. And again.  _ But how? _

_ As long as you’re touching me _ , Billy explained,  _ you can breathe underwater. At least for now. _

_ Did you do this with anyone else? _ Steve asked, taking care not to stop touching Billy’s skin, as per his warning. 

_ It wouldn’t work with anyone else _ . Black eyes and black claws pulled him closer, enrapturing. The fallen monster of Steve’s gut stirred irrevocably.  _ No one but my mate _ . 

_ Your… _ Steve’s eyes widened and, for a second, he forgot, letting go of Billy completely in his surprise, struggling to get away from him. 

He took a breath in wrong, filling his lungs with  _ something _ , something that didn’t belong there, he-

Everything went black. 

_________________________________________________

Steve woke up wet, lying at the rock he had been sitting on before. 

He opened his eyes slowly, watching as Billy came out of the water, tail still very red underneath the moonlight. 

He sat up as silence stretched between them. 

“How long?” He asked Billy, who shrugged. 

“Since we met, I knew.” Billy told him, eyes on the moon. “I thought you’d be one of those straight guys I had to fight until we hate-fucked.” He explained. “Clearly I was wrong.” 

He took it all in. “Do you… do you  _ need _ a mate or…?”

“If I want to be able to turn after my eighteenth birthday, yes.” Billy still wouldn’t look at him. 

Steve paused once more. “Why me?” 

The siren shrugged. “Beats me. As a siren, I’m more fish than human. I can’t explain to you, how it feels… to just look at a person and  _ know _ .” 

So  _ insane _ . His life was so fucking  _ insane _ . “And Starcourt?” 

“I was possessed because of my heritage. Made me all that more resilient.” He explained. “Also why I healed in a week.” 

“Why are you telling me all this now?” Steve asked, confused. Suspicious, most of all. 

“I wasted too much time.” He explained, water dripping from his hair. The moon cast a particularly flattering light to his frame. “I’m turning eighteen in two weeks.” 

Steve bit his lip. “Tight schedule to make someone who hates you start liking you enough to accept to be your mate, I gotta say.” 

Billy’s smile was blinding, head cocking to the side, all ease and charm. “I don’t think you really hate me, pretty boy.” 

Steve thought he’d swallow his tongue if he lied. Which was probably a siren thing, and also  _ terrifying.  _

“Are you…?” 

“I can’t really harm you, or force you into anything.” 

“That’s a lie.” Steve shook his head. “You beat me up.” 

“Neil has been trying to  _ cure _ me since I was a child.” Billy informed him. “The  _ cure _ he surprised me with that night got me unhinged.”

Suspicious. Suspicious, and ridiculous, and lies, all of them. To be honest, he didn’t care all that much about the beating anymore - dying to save them all kind of overwrote that, a redemption of sorts, combined with the apology - but it was the principle that counted. 

“Can you, like... “ He blushed. “ _ Mate _ someone, and then never see them again?” 

Billy hummed. “You can certainly try.”

That sounded like a threat.  _ Fuck _ . His dick jumped inside his wet pants. What the fuck was  _ wrong _ with him?

“What do you want me to do, Billy?” He asked at last, looking away from him. 

Billy slid himself back on the water until it reached his chest, turning to Steve. “I just wanted you to have the whole information before you decided anything.” He answered. “Sounded fair.” 

Steve nodded. Feeling dismissed, he stood up, patted his pocket for the Beamer’s keys. 

“See you around, Hargrove.” He said, turning his back to the lake, to the moon. Those hypnotizing eyes. 

“See you in your dreams, pretty boy.” Billy’s voice told him, and, well. 

_ That _ Steve didn’t doubt  _ at all _ . 

_________________________________________________________

After a tortuous night of waking up multiple times to his dick leaking painfully on his bed, Steve made his way to work. As soon as he was free of that one, though, he drove to the arcade. 

And by the way Max’s eyes widened at the sight of him, she  _ knew.  _

“You’re coming with me.” He grabbed her by her sweatshirt, ignoring Dustin’s protests. 

Steve sat her down on the hood of his car and crossed his arms over his chest, waiting. 

“What?” She asked, avoiding his eyes. Clearly faking. 

“How long?” Steve asked, mad as hell - if not necessarily at  _ her _ . At  _ something _ . His damned fate, maybe. 

“How long what?” 

“How long have you know that Billy is merfolk?” He demanded, leaving her no room to deny it. 

Her eyes widened a little before she cast them down again. “Since I was six.”

“Holy  _ fuck _ , Maxine.” He made a point in drawing out her full name. “And you didn’t think it was, I don’t know,  _ relevant _ to mention? Especially after what happened at Starcourt?” 

“And, what, let Billy be more of a lab rat than he already was?” She protested. “He may be an asshole, but no one deserves that fate, okay?” 

He groaned and let his head fall back in frustration. Stupid kids and their stupid secrets. “What about me? Did you know about me?” 

“What about you?” She frowned. 

Steve’s anger deflated. She didn’t know. 

And, for fuck’s sake, he had to tell  _ someone _ . 

He sat beside her, staring at his hands. Remembering black claws, black eyes and a maddening smile. “I’m his mate.”

Her mouth fell open. “ _ Oh _ .” 

“Yeah.” Steve sighed. “Could breathe underwater with him and all that.” 

“Well, see the bright side.” She suggested with a shrug. “You’re royal family. King of the whole Pacific Ocean.” 

“I’m  _ what? _ ” Steve opened his eyes quick, too quick, a headache settling between his eyes. 

She smiled, sheepish. “Ops? Guess he didn’t tell you that part, huh?” 

___________________________________________________________

“He’s  _ what _ ?” Steve insisted, wondering if he was too young to have an aneurysm. It certainly didn’t feel like he was too young for anything at this point. 

“His mum was the princess, but she walked away from the sea because she fell in love with Billy’s dad, her mate. He didn’t know what they were until Billy was born.” Max explained to him, little feet dangling away from the floor. “And then his grandfather died, and it was time for her to go back to the sea.” 

“So she walked away and left Billy with Neil?” Steve frowned. 

“She had no choice on the matter, since Billy would have to live on dry land as soon as he reached puberty. By then she thought Neil’s love for her and for the child could stop him from turning against them. That’s what Billy thinks, anyway.” Max shrugged. “She was wrong. Neil decided Billy was a freak that should be cured, and have been struggling to get him away from water, and injecting weird stuff on him, ever since.” 

Steve rubbed his forehead vigorously, trying to make sense of all of that. “And where is she now?” 

“A man came into the house one day to talk to Billy, right before we moved to Hawkins. Said his mother was dead and that it was time for him to find his mate and take the throne.” Max made a sad face, remembering it. “Neil yelled him out of the house, and next thing we knew, we were here. In the middle of the continent, as far from the sea as Neil could get us.” 

That sounded… cruel. Forcing a fish to literally live out of the water. Billy, just like everybody else, couldn’t be blamed for the species he was born as. Just like Steve was a human, Billy was a siren. 

“You believe him?” Steve asked her.

She shrugged. “I mean, I saw the guy. I saw Neil inject Billy with stuff more than once. And I’ve seen him turn.” Max explained. “So yes, I believe him.” 

One more thing to confirm, though. “Did he ever take you to breathe underwater?” 

Her jaw fell open once again, and he felt something warm in his chest for that. It wasn’t a lie, then. That would only work with a mate. 

“Thanks for your help, Max, but I gotta see a guy about a thing.” He pulled her from the hood of his car and walked into it, turning the engine on. 

“Steve!” She called out for him as he turned to get to the road. “Steve! Steve, there’s something you need to-!”

He drove off, not letting her speak. 

If he heard one more supernatural word on that particular day, he’d burst a vessel in his brain. But maybe that’s wasn’t such a bad thing. 

It would save him a lot of decision making to do.

_____________________________________________________________

“There’s something wrong with you, dingus.” Robin warned him on a quiet afternoon at Family Video. “You’ve labeled that tape wrong at least four times already.” She sat in front of him. “Spill.” 

“Nothing to tell.” He grumbled, not bothering to hide that he was upset. 

It wasn’t like it could get any worse, right?

“We have a customer, come on.” He passed her as the bell rang, not even looking up from the tape he was holding. “Family Video, how may I help y-” 

“Hi, pretty boy.” 

Fuck. Billy. 

“H-hi.”

“I came to pick up these.” He handed Steve a small piece of torn paper. “Max’s list.”

“S-sure.” Steve agreed, going around the shelves to find them. 

_The Little Mermaid._ _Splash. Miranda. Mr. Peabody and the Mermaid._ Nice, Maxine. Real subtle. 

He got the tapes and put them inside the bag. “It’s four seventy-eight.” 

“Thanks.” Billy answered, handing him the money. 

He turned to leave, but stopped right at the door, turning back around. 

“You can tell her.” He said, looking from Steve to Robin. “She kept stuff from Russians. I’m sure she can keep stuff like this, too.” 

Then, he turned and left, bell jiggling as the door shut behind him. 

“Alright, dingus.” She locked the door behind BIlly, turning to Steve with her arms crossed. “Start talking.” 

_________________________________________________________

“You mean you’re  _ mate _ to a  _ siren prince _ ?” She frowned after his explanation. 

“Apparently.” He agreed, sitting beside her on the counter, eyes shut. 

“Holy shit, Steve.” She chuckled. 

“Stop laughing!” Steve slapped her forearm. “I mean it.” He rubbed his eyes. “Why me?” 

“My best explanation is that you, as a supernatural being yourself, attract supernatural things, Steve.” She shrugged. “No, seriously! Think about it-”

“I am  _ not _ supernatural, Robin.” He rolled his eyes. 

“No, but your  _ mate _ is.” She teased him. 

“I’m serious!” Steve cried. “I mean. What am I supposed to  _ do _ ?”

“I don’t know.” She admitted. “Seems cruel to be the cause of him never being able to be home anymore. But at the same time, it’s not your responsibility.” Robin shrugged. “It’s your choice. I mean, if there is one to make.” She shrugged. “I never thought you’d be in doubt over something like this.” 

“What do you mean, in doubt?” Steve asked, confused. 

“Yeah.” Robin shrugged. “You’re clearly struggling to make a choice.” 

“I’m not!” Steve stood up quickly. Too quickly, giving himself a dizzy spell. “I’m not! I’m not…  _ fucking _ him!” 

“Well,” She sat up, looking as a couple of boys knocked on the glass door, asking for them to open it. She walked there slowly. “For someone who isn’t thinking about fucking him, you sure stare at his ass quite a lot, dingus.”

That being said, she opened the door, letting the customers in. 

And Steve couldn’t even do anything to keep the image of that ass - covered by scales or jeans - out of his mind. 

_______________________________________________________________

The dreams were becoming a constant. 

_ Hey, pretty boy _ , was giving him a pavlovian reaction erection after seeing them so many times wrapped around his dick, in his dreams. Those claws on his back, that smirk making his dick jump, all of him  _ consuming- _

“Steve, you okay?” Robin asked him after he fell asleep on the counter, dreaming again. 

“Yeah.” He nodded, but the bags underneath his eyes were the reason she didn’t believe him. He knew that. 

“Can you come help? I have to-”

“No can’t do, sorry!” He said, quickly slipping into the employee’s only bathroom, desperate to hide his tenting erection. 

All that had to stop. 

And he knew just who to talk to.

______________________________________________________

“This has to stop.” He growled as soon as Billy was in his sight. The boy had been working at a mechanical shop, and, apparently, taking a cigarette break at this point. 

“It won’t.” Billy said, smoke coming from his mouth with each word. 

“Why not?” Steve was frustrated out of his freaking mind. 

“Because I’m not doing anything.” Billy explained, pausing. “In a few days it’ll all go away.”

“When you turn eighteen.” 

“That’s the day.” Billy agreed. 

“I can’t  _ not sleep _ for another five days, Billy. I’m going insane as it is.” 

The blond boy shrugged. “Nothin’ I can do.”

Steve groaned and pulled on his hair with both hands. 

Billy, in return, offered him a cigarette. Which Steve accepted. 

“Do you have those…  _ dreams _ , too?” Steve asked, avoiding Billy’s eyes. 

Billy looked so nonchalant. “Since before met you.” He admitted. 

That made Steve open his eyes. “Really?” 

He evaluated the older boy for a moment. “Yeah. The day before we met I dreamed of your face.” He said, no expression to him at all. “Ever since I have the occasional dream.” 

“Has it been getting worse lately?” Steve asked, curious. A little flattered. “Because of your upcoming birthday, I mean.” 

Billy just nodded in response. “Siren nature, I’m guessing.” 

Steve licked his lips slowly. His eyes caught on Billy’s, the way they curled around the smoke. They looked so....

“So there’s nothing we can do?” He asked, turning to Billy. “To, like. Make this better?” 

“There is one thing.” Billy admitted. “That won’t make us bound, but may tire us up and sate this need enough for you to be able to sleep.”

“What is it?” Steve asked. Ready to try anything. 

But Billy’s smile showed too many teeth. 

That’s how he knew he was in trouble. 

_________________________________________________________________

That’s also how he ended up at the back of the Camaro, wildly making out with Billy Hargrove. 

Jesus fuck, the guy was  _ hot _ . Like,  _ insanely _ hot, in a way that made Steve want to lick every single inch of him. 

His thighs were thick under Steve’s ass, his ass  _ glorious  _ underneath his hands, his lips so full and soft under Steve’s desperate  _ devouring _ of his mouth, and the erection Steve felt against his own made him question everything he knew about himself. Because maybe he had been willing to kiss a guy or suck his dick before, but right then his mouth  _ salivated _ for Billy’s and that just wasn’t normal for him. 

Billy’s hands squeezed his ass and he  _ moaned _ , friction between their denim-covered dicks increasing tenfold. 

The windows were already fogged by their warm breaths. Touching Billy was like a touching a livewire, but without the pain - he felt alive, electric, every corner of his body felt sensitive, in a very good way. 

“Come on, pretty boy,” Billy gasped. At least he sounded just as wrecked as Steve. “Come on, I know you can come like this, come on-”

But Steve wasn’t about to be the first one to come in his pants, no sir. 

So his lips latched into Billy’s pulse point, sucking, licking, biting, almost at the same time as his hands found the other boy’s nipples through his shirt, pinching them. 

Billy threw his head back and moaned, arms trembling. With more of his neck exposed Steve bit over the side tendon, earning the most delicious whimper.

Steve directed his hand to cup Billy over his jeans and squeeze slightly, right-

“ _ Fuck! _ ” Billy would have screamed if his voice didn’t stay clogged in his throat, completely wrecked. 

Jackpot. 

Steve smiled to himself as Billy came in his pants.

Which was, you know, his own downfall, because he came at the sight of Billy’s climax. 

In his defense, it was an extremely erotic sight, okay?

Took him around two minutes - or at least he thought - to gather himself back together and lift his face from where it had been, up against Billy’s shoulder. 

As soon as he did, he yawned. 

“Mission accomplished.” Billy said with a smug grin, eyes also half-lidded, looking a little tired. Thinking about it, the anxiety of maybe missing a part of who he was would probably make Steve have trouble sleeping, too. 

He had been mentally dreading the drive back to his car, going back home and taking a shower - he was so cozy and warm right there, any activity might wake him, and he hadn’t slept in  _ days _ \- when Billy, somewhat awkwardly, maneuvered them both to his backseat. 

“What are you doing?” Steve asked mid-yawn. 

“I don’t know about you, but I’m not going back home to one of my father’s  _ cures _ .” He said, settling with an arm around Steve’s waist. It felt… nice. 

“So you’re sleeping here?” Steve asked, trying to sound a little more energetic and indignant than he actually felt. The yawn cut his effect, though. 

“Yeah.” Billy confirmed. “And if you’re not keen on walking all the way home in this weather, I suggest you do the same.” 

And, well. Steve knew he should have put up more of a fight. But he was sleepy, he was warm, he was relaxed. 

Just a couple of hours, he promised himself. A couple of hours and he’d get out of there.

_________________________________________________________

He was lucky it had been a Friday, because they both slept soundly ‘til noon. 

_________________________________________________________

“So you’re fucking him now.” Robin concluded after his retelling of the night, parting her croissant with her hands to bite into the chocolate part first. 

Steve rolled his eyes in response. “It was  _ one night _ .” 

She leaned forward, eyebrow raised. “Then look me straight in the eyes and tell me that you don’t plan on doing it ever again.” She dared him. 

He stuffed all of his doughnut inside his mouth, chewing slowly, and most likely looking like a chipmunk with his cheeks filled with nuts. 

And, yes, Robin was his  _ friend _ , but it was still  _ very rude _ of her to laugh that loudly right to his face.


	2. Part II

PART II

Billy’s birthday was approaching. Each hour closer to it was an hour Steve’s anxiety grew exponentially. 

It was almost like his body knew. 

_______________________________________________________________

“Steve?” Max’s voice was cry-ish, raising his heartbeat through the roof. 

_Billy_. “What happened?”

“Can you come pick us up?” She asked, her sniffles coming clear as day through the receiver. 

Steve got his keys from his pocket, turning off his TV. 

“I’ll be right there.” 

________________________________________________________________

“What happened?” Steve asked as soon as he parked outside the Mayfield-Hargrove residence, walking to her, who was waiting for him at the front porch. 

“Neil gave him something, and when he didn’t wake up again, he forced my mom into his car and left.” Max explained, guiding Steve inside. “I already called Hopper on Neil, but normal doctors won’t be able to help Billi. We gotta take him to the lake.” 

“Max…” Steve started as he saw Billy on the floor. He didn’t look pale, and he was breathing. All good signs. But doctors were the clear way to go there, at least while he looked like a human. 

“He _asked me_ , Steve. Being in merman form always helped before.” The girl insisted, eyes brimming with tears. “ _Please_.” 

Steve nodded, his own heart clenching, remembering the sweetness of the smile Billy had offered him that day on his car. How they had slept so well together. 

He nodded at her and got him on his arms with difficulty, but he could handle it. They walked quickly and Max opened the back door for him to put Billy into. Then she sat on the passenger seat, wiping her tears, a determinate expression covering her face instead. 

And Steve? 

Steve drove. 

________________________________________________________________

She guided the path to the lake expertly, like she’d lived there all of her life - which was somewhat concerning, considering how dangerous that lake actually was - with Steve trailing right behind her, Billy precariously hanging from his arms. 

Once they got there and Steve put him down, the girl went straight to Billy’s clothes, starting to take them off. 

“What are you doing?” He asked, terrified. 

“Steve, in any other situation I’d care, but this is an emergency and is my _brother_ . I don’t care if he’s naked if it’s going to save his life, and I don’t see how he could turn legs into a tail inside _jeans_.” She explained quickly. “So boundaries aside, I have other priorities, okay!” 

And, well. Steve didn’t have any brothers, but he’d do the same for Dustin and not care a flick, so.

He started helping her, taking off Billy’s jeans and underwear before taking him into his arms again. He couldn’t just drop him into the water - if he didn’t turn, he could drown - so Steve entered it holding him, each step a freezing surprise to his overwhelmed system. 

Billy looked ethereally pale underneath the moonlight. He only noticed the lack of breathing on his part right then, too worried about getting him in the lake before. 

Something dirty, desperating, cloyed his throat. _Fuck no_. No, no, that couldn’t be happening-

He wasn’t the best person in the world, Billy, but he got dealt a bad hand. He got dealt a _horrible_ hand and did what he could with it. Yes, he made mistakes on the way, but he learned from them and now… now he’d never get to experience anything but the hell he had under Neil’s thumb. No future to erase the bad past, no time for him to clean his ledger and be a little happy. He’d seen the error in his ways, he asked for forgiveness and changed his patterns, and for what? To die a stupid death because his father _poisoned him?_

Steve looked up, his eyes blurry - from tears, he noticed. The moon mocked him from up there, full enough for him to blame her. 

“He’s one of yours!” He told her, sniffing. He probably looked insane, but he couldn’t care less. “He’s one of yours and you did _nothing!_ Why?! Why didn’t you do anyth-”

“Steve!” He heard Max’s voice calling him out, but it was too late. 

Something latched to his ankle and pulled him under, right to the deepest center of the lake, completely underwater. When the pulling stopped, he could barely see the moon shining on top of him. 

Then Steve noticed it: the translucent figure of a woman calmly staring at him. 

_Steven Harrington._ Her voice came straight to his head, just like Billy’s, under the water. The woman was beautiful. She had the same hair as Billy, the same eyes. _You call in my son’s behalf._

 _I do._ He answered in his thoughts, heart trying to carve a way out of his chest with each beat. _Please save him_. 

_Don’t you think he will be better with me?_ She asked him, a sad expression on her face. _He will never be alone again. Me and his grandmother will take care of him for eternity. He will not have to suffer living alone and as half of himself_. 

_He has Max_ , he tried. _She loves him_.

 _She does_ , the woman agreed with a nod. _But she can’t stay at his side. She can never follow him into the sea._

He hesitated. _And I can?_

She smiled. _You are seeing this from the wrong point of view, Steven Harrington. A mermaid’s mate is not owned by them. A mermaid is the one owned by her mate, because her devotion transcends time and space._ Her had brushed his face, soft as smoke to his skin. _He will be yours until the stars cease to shine._

Steve gulped. _That’s a lot of responsibility._

 _I’m glad you see it that way._ Her smile grew. _I have asked the Moon to give my son a better mate than the one I had. And you don’t remember, but we have met before_.

He blinked, his thoughts rushing. A sunny trip to California. Staying in a hotel with a pool, but convincing his mom that the had to do to the beach. Playing near some rocks while his mother read a book. Seeing a blond boy with a red tail playing with a woman who had the same hair as him. Blushing when the kid threw him a radiant smile, excited that he was there. 

_That was you?_

_I knew Billy was yours as soon as I saw you_ , she explained easily. _All I could do was hope that you deserved his heart_. 

_I don’t-_ Steve bit his lip. _We’re not-_

 _Maybe_ . She agreed. _And yet, here you are, crying and screaming at the Moon for him._

He stopped, trying to think. _What do I do?_

But she started to disappear. _Just make sure my boy is never alone again._

He nodded. 

He emerged on the lake’s water like a diving bird, in a burst of force that wasn’t really his.

Looking around he saw Max holding Billy with his legs into the water, torso over her wet frame over a flatter rock.

Steve swam there as quickly as he could, crawling the rest of the way close to her. 

“What happened? I thought you had drowned!” Max asked, eyes rimmed red. 

“Doesn’t matter.” He answered, holding Billy’s face to his. He wasn’t breathing. “I know what to do.” 

“Then do it!” Max asked him, eyes wide. 

Steve nodded and put his lips over Billy’s, blowing all the air from his lungs to his. Every single drop, until Billy’s eyes shot open and he gasped desperately for the air -- or the water -- that served as a buffer between him and the world. 

____________________________________________________________

They were silently drying themselves at Steve’s place, Max already wearing Steve’s clothes near the fireplace at the living room. 

“We found them at the interstate.” Hopper informed them as he walked in. “But your step-mom is refusing to press charges against him.” 

“What?” Steve felt the indignation for Billy, even though he didn’t seem surprised. “So he’s just going home?”

“I can’t do anything, kid.” Hopper sighed. “You know I believe you, but we have no proof that he tried to kill Billy _or_ that he actually kidnapped his wife.” 

Steve turned to Billy. “You can’t go back there.” 

Billy chuckled darkly. “What option do I have, Harrington?” 

“You stay here.” He insisted, ignoring the way Hopper’s eyes widened. “With me.” 

The younger boy looked sad. “You know why I can’t do that.” 

“Billy-” 

“No, pretty boy.” He handed Steve his towel back. He looked at Hopper with a resigned expression that Steve _hated_ seeing on him. “Take us home.” 

______________________________________________________

Steve punched the wall. He smoked, he drank his father’s liquor. He couldn’t sleep, thinking of Billy and Max inside that house with that man. 

Morning came to him tensely watching the sunrise from his front porch, smoking his fifth cigarette of the night. 

But then the phone rang. 

Expecting the worst, Steve picked it up and placed it on his ear. “Hello?”

“He’s gone, Steve.” Max’s voice informed him. 

“Gone _how?_ ” No, not again. He almost lost Billy one too many times. 

“He got into a huge fight with Neil last night when we came back.” She explained. It didn’t seem like she was crying, but maybe it was shock? He tried not to read too much into it. “He threatened to kill Neil if he ever touched me, said Hopper would make sure no one ever found out it was him. Then he got all his stuff into the Camaro and drove away.”

“Did he tell you where he was going?” Steve asked her. He wasn’t sure why. 

He knew _exactly_ where Billy was going. It was right there, like a compass in his gut. 

“No.” She told him. “But I think I know. There was this woman back in Santa Monica who insisted he called her grandma. I think he’s going there.” 

“Give me the address.” Steve demanded, pen and paper on his hand. 

She didn’t know it, but gave him the instructions on how to get there, which was good enough for him. “Thank you.” 

“Steve,” Max sounded dubious. “What are you going to do?” 

“I’m gonna find that idiot.” Steve answered and hung up, going to pack his bags. 

_______________________________________________________________

“Robin, no.” Steve tried as he saw her arrived with her own bag packed at his front porch, about thirty minutes after he called her. “People will say we eloped, or that I kidnapped you.” 

“Fuck people, dingus, you’re not going to California to find your boy toy without me.” 

“Boy t-? Listen, Robin, this is serious.” Steve shook his head. 

“So am I.” She entered his car, sitting on the passenger seat and smacked the door twice with her spread hand.

Steve groaned and entered the car, turning the engine on. If she’d be like that, then fuck it. “I hope you know how to drive.”

“I’m a quick study.” She assured him like it was nothing. Then proceeded to fuck with his radio until she found something that please her, singing along and nodding her head to the melody. 

“You never really told me what happened.” She spoke after a while, right after they passed the _you’re leaving Hawkins_ sign. 

Steve’s heart was on his throat. “What happened to what?” 

“Last night.” She explained. “What made you change your mind about Billy.” 

“Who says I changed my mind about Billy?” He challenged. 

Her raised eyebrow answered that question. 

“Alright. Well. Don’t call me crazy, please.” 

Steve took a breath. 

And told her everything. From his anxiety to Max’s call, to the talk he had with Billy’s mother, Hopper arriving. _Everything._

“So you’re telling me you promised a merman’s dead mother that you’d never let him be alone again, and now he ran away.” She nodded, taking it all in. “Are you mating him, then?” 

He shut his eyes for a second. “I don’t know.” 

“I think you do.” Robin said. 

“Robin-”

“Dingus, I’m not judging.” She looked through her window, a small smile to her lips. “I mean, I’m a lesbian, but even _I_ noticed how nice his ass is-”

“Stoop!” He groaned. 

“I mean it!” Robin laughed. “If I had to objectively pick who’s the hottest person in Hawkins, I’d have to say him. It’s only fair.” Then she touched his forearm gently. “We’re gonna find him, dingus. Alright?” 

Steve nodded. “Yeah.” 

“And then when you fuck him you gotta tell me _everything_ , because honestly I’m a little curious if Hawkins’ rumor mill is right about his prowess-”

“Robin!” He tried to chastise her, but couldn’t help the laughter bubbling inside his belly. 

“What, Steve?” She asked him, still chuckling. “I mean. Rumor has it he has a dong the size of-”

Steve almost ran them off the road. 

____________________________________________________________

They took turns driving once Robin got a hang of the gear stick. Steve couldn’t sleep anyway, so he drove without pause while Robin slept or rested. They only stopped to buy food and to go to the bathroom. 

Which was why, in half the usual driving time, they were in California.

California was… sunny. Bright, golden and blue everywhere, the greenest greens Steve had ever seen. He understood why Billy loved it so much. 

Not to mention, of course, the ocean. Glittering underneath the sun like a big blue diamond, calling them back. 

_________________________________________________________

He had to ask a couple of people, but he finally found the house. 

Which was empty. Abandoned, by the looks of it.

“Do you really think he got here?” Robin asked him, looking around. 

By then a boy stopped on his bike, looking at them. “Looking for Mrs. Greer?”

“Yeah.” Steve told him. “Old friend of ours.”

“Sorry, man, she passed a couple of months ago.” He answered. “But she’s sure popular today.”

“Why, anybody else came here?” 

“Yeah, a guy came in today.” 

“How was he?” 

“I don’t know, man.” The boy shrugged. “But he had the sweetest ride, what’s the name of that car-”

“A Camaro?” Robin tried. 

“That’s the one!”

“So he was here.” Steve looked at her, then back at the boy. “Do you know where he went after here?” 

“Nah.” He shrugged. “But he drove towards the beach.” 

“Thanks!” Steve said and got into the car, waiting for Robin. 

“Dingus, the beach is huge.” She reminded him as he drove. “How the hell do you plan on finding him?” 

“I don’t need to look.” Steve informed her. “I know exactly where he is.” 

___________________________________________________

It took him a couple of tries, but he found it. The hotel he had been with his parents all those years ago. 

Then he looked at the beach, searching for a very particular stone. 

“Wait here.” He asked Robin once he found it. 

“Alright. I’ll be at the ice cream shop!” She told him, walking back to the car. “You’re paying!”

Steve walked up to that stone, and then around it, uncaring of his wet pants. 

“You are an idiot.” 

Billy opened his blueblue _blue_ eyes very slowly. “Hi, pretty boy.” 

____________________________________________________________

“We gotta talk.” Steve sat down where Billy was laying, what he hoped was a threatening expression.

Billy didn’t look impressed, shutting back his eyes. “Go away.” 

“No. I’m your mate, remember? I get a say on this too.” 

“Correction: you are _not_ my mate.” Billy answered clearly. “We got nothing to talk about, pretty boy.” 

“Yes we do.” Steve insisted. “That night I took you to the lake, I talked to your mother.”

Billy frowned. “My ma is dead.”

“I am aware.” He growled. “She talked to me anyway. Said we met before. Right here. That she knew we were mates.” 

The blond boy finally sat up, eyes bluer than the sky above them. “Why didn’t she take me?” 

“Because I asked her to.” Steve licked his lower lip, nervous. 

Billy was frowning again. “Mighty honourable of you.” He scoffed. “Egoistic, too.” 

“I know, I know! She told me you’d be fine with her and your grandmother, but I just couldn’t-” His throat clogged. 

“Couldn’t what, Harrington?” 

“It’s Steve.” He corrected him firmly. “And I couldn’t lose you again.”

Billy watched him carefully. “You don’t know what you’re saying, Harrington. You look like you haven’t slept in days.” 

“Stop telling me how I feel.” Steve demanded, grabbing Billy’s forearm. “Stop.”

“I won’t when you start making sense, Harrington-” Billy was about to stand up when Steve pulled him back down and sat on his legs, effectively stopping him from moving. “The hell are you doin’?”

“You won’t trust my words, maybe you’ll trust my actions.” Steve said. 

Then he kissed him. 

Steve was enjoying the kiss, don’t get him wrong, but he felt the shift. He felt when Billy’s legs tore his jeans up and became bigger, smoother, colder, right underneath his ass. 

And when he let go, he knew what he’d see. Black eyes, black claws, little fangs. 

“What did you do to me?” Billy asked him, looking at the torn remains of his jeans around the red, scaled tail. 

“Well, I mean,” Steve bit his lip, amused. “You know when a person likes another person, sometimes, they kiss-” 

“This is daylight, not full moon.” He protested, looking around, but the beach was empty at that time - at least where they were, inside the sea. “What did you _do_?” 

“I just decided that I’m your mate, and that you should be able to change whenever you want.” He answered. “And it’s, in fact, your birthday today. But, you know. Before you change back again, I really should get you some pants, because I’m not the _sharing_ type-” 

Billy kissed him. And then dunked him. 

____________________________________________________________

_A year later_

_Come on, Billy, we gotta be quick,_ Steve said, but his hand was already inside the scaly flap that hid Billy’s cock, palming him hungrily. 

_I’m the King,_ Billy argued, lips on Steve’s, devouring him. _They are going to wait for me._

 _Yes, well, but they’ll know-_ Steve protested, biting his own lower lip to avoid making a loud sound at Billy’s hands squeezing his ass globes apart, fingers finding his hole still loose from the previous night. 

_What’s so bad about they knowing I fucked you so loud you screamed, huh?_ Billy teased him, fangs working his neck, tongue licking it all clean. _Fucking hell, you taste amazing_.

 _Billy, come on-!_ Steve insisted, spreading his legs a little so he’d fit over Billy’s tail over his throne, where, apparently, siren’s leaders from all the other seas were coming to greet the Pacific Ocean’s king for the first time. 

Underwater, Billy slid into Steve with ease, groaning loudly. His arms held Steve by the waist, leveraging him up and down on his dick, quicker and quicker, tongue touching his canine quite devilishly. 

_W-what?_ Steve asked him.

In lieu of a response, Billy turned Steve so he was facing the throne room, back to Billy’s chest. He then proceeded to place his hands on the back of Steve’s legs, raising them so he’d have no purchase. So he’d have to just take it. 

_The power has- fuck- really been messing with- uugh- your head._ Steve complained, hands struggling to find something to hold on to - finding only the throne’s armrests. 

_Maybe._ Billy agreed, one hand pressing on Steve’s lower belly just _right_ to feel just how deep his dick reached inside of his mate. _But since I was quite literally-_ He gasped. _Made for you, I’d say you wouldn’t have me any other way._

Steve hit Billy’s arm, making him laugh. Then he reached back to his nipples, twisting one, effectively triggering the king’s orgasm. 

He came right after that, with Billy’s hand around his dick, cock still lodged deep into the human’s body. 

After a few moments of just breathing, Steve started to move away from him. 

_Come on, Robin is waiting for me._ Steve hit him in the arm to get him moving as well. _You know how she gets when I’m late_. 

Billy groaned. _Robin has to chill the fuck down_. 

_She would if you’d let me get my assignments done in time-_

_Alright, alright_ . Billy conceded. _Let’s take you up before your work-wife nags me to death_. 

____________________________________________________________

“You’re late.” Robin told him as he came out of the water in his swim trunks. 

“I know, I’m sorry.” 

“And by the way you’re walking, I know _exactly_ why you’re late. Which is unfair, because I’d also rather be being fucked instead of being here, on a beach, trying to make this assignment _work_ so we can avoid _flunking out_ from UCLA, but alright, because you’re the _king of the Pacific Ocean’s bitch_.” 

“I’m his _mate_ , there’s a big difference there.” Steve sat down, drying his hands to get to his notebook and paper. 

“I see none.” She decided pettily.

“Did you know that he can’t even get it up for anybody else until I die?” Steve tried her, one eyebrow raised. 

She rolled her eyes. “Cause that’s the most important thing.”

“It’s quite important.”

“Seriously now, dingus.” She put her notebook down and looked at him. Really _looked_ . “I know we’ve moved out here and all, but… are you happy?” She asked. “I mean. You always complained before when supernatural things happened to you, and that, with Billy? It’s never gonna be completely normal. He’ll have to be gone from time to time, so he won’t be able to hold onto work, and from what he told me he’s been fucking you exclusively because male sirens _can_ , _indeed_ , get pregnant, so I’m just-”

“Robin.” Steve interrupted her, a smile to his face. “I’m happy. I swear.” 

She nodded. “Good. That’s good, dingus.” And then she looked down. “Now, this assignment is about… _fish?_ ”

Steve laughed, looking at the theme. “ _That_ I know about.” He assured her cockily. “Let me handle it.” 

And Steve could barely _believe_ he was doing this. 

Then again, with his curiosity history, it wasn’t all that unbelievable at all that he’d get into trouble, someday. 

He was just glad it all paid off like it did. Because, honestly?

He wouldn’t have it any other way, either. 

**Notes for the Chapter:**

> I hope you enjoyed it!  
> See yall next time :)


End file.
